Figure 4.

Networks become more similar during, and between, seizures. A, Two examples of networks from a preictal interval (unshaded) and ictal interval (shaded) from two different seizures of a single subject. Visual inspection suggests that the ictal networks are more similar both within each seizure (i.e., within each shaded region) and between the two seizures (i.e., between the 2 shaded regions) compared with the preictal networks. The arched (straight) lines indicate example intra-seizure (inter-seizure) comparisons. B, The similarity between networks within each interval of the same seizure (i.e., intra-seizure similarity, solid curve) and between intervals of different seizures from the same subject (i.e., the inter-seizure similarity, dashed curve). The intra-seizure similarity increases during seizure; networks become more similar within ictal intervals compared with preictal intervals. The inter-seizure similarity, which compares networks from the same interval but different seizures of a subject, also increases during seizure. For both curves, circles denote the mean value (n = {82059, 10222, 30666}) of intra-seizure comparisons for the preictal, ictal, and postictal intervals, respectively, and n = {277537, 40169, and 120507} inter-seizure comparisons for the preictal, ictal, and postictal intervals, respectively, adjusted for differences in subjects; the vertical lines denoting the SE are no larger than the black or gray circles. Statistically significant changes from the preictal value are indicated in gray (see Materials and Methods).